A gravity racer or soapbox is a motorless vehicle which is raced on a downhill road either against the clock or against another competitor. The vehicles are propelled by gravity.
A gravity racer or soapbox is a motorless vehicle which is raced on a downhill road either against the clock or against another competitor. The vehicles are propelled by gravity.
Originally, gravity racer cars were built from wooden soap (or apple) crates and rollerskate wheels, but have grown more sophisticated over time, with materials like aluminium, fiberglass and even CFRP being used.
In the United Kingdom a gravity racer car has been called a buggy, trolley, cart. It is currently popularly called a soapbox. In Scotland and northern England it has also been called a bogie, cartie/cairtie, guider or piler. In Wales it is often referred to as a gambo. In Australia they are called billy-carts, and in Brazil it is known as rolimã.
In addition to being built by children, there are organised competitions and races ("soapbox or billycart derby") that often engage the enthusiasm of adults. However, these are usually entered into in a spirit of fun rather than serious competition. Often they will be fund-raisers for charity. Many, but not all, events impose the following rules:
Soapbox cars weigh an average of 150 pounds (68 kg) and reach top speeds of 20 to 30 mph (30 to 50 km/h). [1] Many cities have permanent tracks where drivers compete for prizes.[ citation needed ]
A typical gravity racer cart is usually made of steel, and has 4 wheels, arranged as a fixed rear axle, and a steerable front beam axle - usually with a very simple single central pivot. A seat is arranged at the back, and perhaps the seat area is enclosed, as in the original soap-box design. More sophisticated designs might employ a fully enclosed body. The types of wheels employed vary according to what can be obtained easily - wheels from baby carriages, pushchairs, prams, and discarded bicycles being common. Ready-made wheels are also available from hardware suppliers. Steering is typically actuated using a rope connected to the ends of the steerable beam (which can then double as a useful manual pulling device).[ citation needed ]
More sophisticated steering methods are sometimes seen. Brakes are also commonly used, and most soap-box cart racing contests require these. Often a simple friction brake operated by a lever which bears on one of the tyres is all that is required under the rules.
Gravity racer carts are unpowered, and are either pushed by willing helpers, or are run down a suitable slope. Races will usually take place downhill and the most efficient and skillfully driven cart will win - gravity applying equally to all.
Gravity racer carts also make great construction projects for children, requiring only an intuitive sense of engineering, and a few basic construction skills. There are also pre-designed kits available, though for many this defeats the purpose of the exercise.
Recently, more advanced gravity racers are beginning to emerge. These, intended for competition in the major soapbox races, are sometimes made of carbon fibre and feature a monocoque design, although most use a more traditional chassis or spaceframe design with bodywork made from materials such as plywood, corrugated plastic or similar. Examples of such soapboxes include the Lotus 119c and the Formula Gravity VXR Nimbus. [2]
In Australia billy carts tend to conform, even in the 21st century, to a more traditional or rudimentary specification often being constructed informally by juveniles from found or inexpensive materials with minimal adult input and used without safety equipment. However even when construction of vehicles is more formally organised, such as for the annual Blacktown and District Cub Scout Billy Cart Derby at Rooty Hill, NSW the vehicle is still constructed to a deliberately relatively unsophisticated design, although safety is a consideration.
In Indonesia, billy carts are also known as 'gokar'. They are raced in different regions as a community social activity. The form of the cart is similar to the Australian one. However, the wheels are often motor cycle wheel bearings.
In Brazil, gravity racers are known as "carrinhos de rolimã." Traditional designs are very minimalistic, with an open board-like body and wheels made up of naked ball bearings (no tyres allowed), usually discarded parts obtained from auto mechanics.
The first recorded gravity race took place in 1904 in Oberursel (Taunus) near Frankfurt, Germany. It was inspired by major motor sports events like the Gordon Bennett Cup and the Kaiserpreis race. [3]
In 1933, Dayton Daily News newspaper photographer Myron Scott of Dayton, United States had covered a race of boy-built cars in his home community and was so taken with the idea that he acquired rights to the event; the national-scale Soap Box Derby grew out of this idea. In 1934, Scott had managed to persuade fifty cities across the US to hold soap box car races and send a champion each to Dayton for a major race, later held in Akron. Scott later went on to work for Chevrolet.
In the UK, gravity racer derbies have recently become more popular, brought to the masses by large events such as the Red Bull Soapbox Race and that held between 2000 and 2004 at the Goodwood Festival of Speed. Now, many small hilly communities organize their own races, such as the Catterline Cartie Challenge in Scotland and the Belchford Downhill Challenge in Lincolnshire, and there are now several dozen known races across the UK. [4] An annual Soap Box Derby has taken place in mid-July at Richard's Castle on the Shropshire/Herefordshire border since 2004. [5] [6] In addition to the local community races, there are a small number of races which attract more serious competitors, such as Cairngorm Soapbox Extreme (held at Cairn Gorm from 2009 to 2012) and the Worlaby Downhill Challenge. These races tend to produce higher speeds than the community races. Gravity racers taking part in Cairngorm Soapbox Extreme in 2011 reached speeds of 70 mph. [7]
A gravity racer obtains its energy solely from the force of gravity (assuming no starting push is permitted), which is effectively equal for any combination of racer design and course. However, performance can be greatly affected by the combined effects of various forms of drag and also the moment of inertia of the wheels, and also of course by the skill of the driver in choosing optimal lines. Drag breaks down into aerodynamic drag and rolling resistance. The latter can be minimised by careful attention to the wheel bearings, tyre sizes and pressures, and brakes (to avoid parasitic brake drag). High tyre pressures and narrower tyres will typically lower the tyre contact rolling resistance, usually at the expense of grip. Larger wheels have lower rolling resistance than small ones, and rolling resistance is also proportional to overall weight. If permitted, a 3-wheeler design will have 25% less rotational inertia than a 4-wheeler, all else being equal. Aerodynamic drag can be minimised by designing a fully enclosed body that reduces the drag coefficient, but given that this can be a highly technical thing to achieve especially for the amateur builder, and given that some aerodynamic drag is inevitable, a heavier cart will always do better than a lighter one with the same drag coefficient - its terminal velocity will be higher. For this reason there are usually class weight limits in most controlled forms of the sport. Since some of the potential energy due to gravity must be converted to the kinetic energy of the rotating wheels, a vehicle with lighter wheels will accelerate faster than one with heavier wheels. If a race is started on some form of ramp, having a tail-heavy car can also improve final acceleration, as the effective height of the centre of gravity of the vehicle is raised.
A bogie is a chassis or framework that carries a wheelset, attached to a vehicle—a modular subassembly of wheels and axles. Bogies take various forms in various modes of transport. A bogie may remain normally attached or be quickly detachable ; it may contain a suspension within it, or be solid and in turn be suspended ; it may be mounted on a swivel, as traditionally on a railway carriage or locomotive, additionally jointed and sprung, or held in place by other means.
An open-wheel car is a car with the wheels outside the car's main body, and usually having only one seat. Open-wheel cars contrast with street cars, sports cars, stock cars, and touring cars, which have their wheels below the body or inside fenders. Open-wheel cars are built both for road racing and oval track racing. Street-legal open-wheel cars, such as the Ariel Atom, are scarce as they are often impractical for everyday use.
A tricycle, sometimes abbreviated to trike, is a human-powered three-wheeled vehicle.
Vehicle dynamics is the study of vehicle motion, e.g., how a vehicle's forward movement changes in response to driver inputs, propulsion system outputs, ambient conditions, air/surface/water conditions, etc. Vehicle dynamics is a part of engineering primarily based on classical mechanics. It may be applied for motorized vehicles, bicycles and motorcycles, aircraft, and watercraft.
A velomobile ; velomobiel, velo, or bicycle car is a human-powered vehicle (HPV) enclosed for aerodynamic advantage and/or protection from weather and collisions. Velomobiles are similar to recumbent bicycles, pedal go-karts and tricycles, but with a full fairing and are not to be confused with purpose-built mobiles for racing or speed records fully faired vehicles with two wheels, generally called streamliners. Streamliners have set many speed and distance records.
Inline speed skating is the roller sport of racing on inline skates. The sport may also be called inline racing, or speed skating by participants. Although it primarily evolved from racing on traditional roller skates, the sport is similar enough to ice speed skating that many competitors are known to switch between inline and ice speed skating according to the season.
The Soap Box Derby is a youth-oriented soap box car racing program which has been running in the United States since 1934. Proclaimed "the greatest amateur racing event in the world," the FirstEnergy All-American World Championship is held each July at Derby Downs in Akron, Ohio with winners from their local communities travelling from across the US, Canada, Germany and Japan to compete. 2023 marks the 85th running of the All-American since its inception in 1934 in Dayton, OH, having missed four years (1942-1945) during World War II and one (2020) during the COVID pandemic. Cars competing in this and related events race downhill, propelled by gravity alone.
The Tyrrell P34, commonly known as the "six-wheeler", was a Formula One (F1) race car designed by Derek Gardner, Tyrrell's chief designer. The car used four specially manufactured 10-inch diameter (254 mm) wheels and tyres at the front, with two ordinary-sized wheels at the back. Along with the Brabham BT46B "fancar" developed in 1978, the six-wheeled Tyrrell was one of the most radical entries ever to succeed in F1 competition and has been called the most recognisable design in the history of world motorsports.
Understeer and oversteer are vehicle dynamics terms used to describe the sensitivity of a vehicle to steering. Oversteer is what occurs when a car turns (steers) by more than the amount commanded by the driver. Conversely, understeer is what occurs when a car steers less than the amount commanded by the driver.
A Formula One car or F1 car is a single-seat, open-cockpit, open-wheel formula racing car with substantial front and rear wings, and an engine positioned behind the driver, intended to be used in competition at Formula One racing events. The regulations governing the cars are unique to the championship and specify that cars must be constructed by the racing teams themselves, though the design and manufacture can be outsourced. Formula One cars are the fastest cars in the world around a race track, owing to very high cornering speeds achieved through the generation of large amounts of aerodynamic downforce. Due to the amount of braking force and the total cornering envelope of a Formula One car, Formula One drivers experience frequent lateral g-loadings in excess of five g and peak cornering forces of up to seven lateral g.
Street luge is an extreme gravity-powered activity that involves riding a street luge board down a paved road or course. Street luge is also known as land luge or road luge. Like skateboarding, street luge is often done for sport and for recreation.
A racing bicycle, also known as a road bike is a bicycle designed for competitive road cycling, a sport governed by and according to the rules of the Union Cycliste Internationale (UCI).
The pinewood derby is the wood car racing event of Scouts BSA. Pinewood derbies are often run by packs of the Cub Scouts program. With the help of adults, Scouts build their own unpowered, unmanned miniature cars from wood, usually from kits containing a block of pine wood, plastic wheels, and metal axles. With the popularity of the pinewood derby, other organizations have developed similar events. Pinewood derby is a registered trademark of the BSA, so most use different names. Each derby has slightly different rules for making and racing their cars. A small industry has developed to provide organizer equipment and awards.
The Mercedes-Benz W125 Rekordwagen was an experimental, high-speed automobile produced in the late 1930s. The streamlined car was derived from the 1937 open-wheel race car Mercedes-Benz W125 Formel-Rennwagen, of which also a streamlined version was raced at the non-championship Avusrennen in Berlin.
The Mercedes-Benz C112 was an experimental mid-engine concept car built in 1991 by German automobile manufacturer Mercedes-Benz as a test bed, similar to the later versions of the C111. Despite using the same chassis code, it was not related to the W112 series of limousines and coupes of the 1960s. The C112 was intended to be the road-legal counterpart of the Sauber-built C11 Group C prototype race car developed for the 1990 World Sports-Prototype Championship.
Wind-powered vehicles derive their power from sails, kites or rotors and ride on wheels—which may be linked to a wind-powered rotor—or runners. Whether powered by sail, kite or rotor, these vehicles share a common trait: As the vehicle increases in speed, the advancing airfoil encounters an increasing apparent wind at an angle of attack that is increasingly smaller. At the same time, such vehicles are subject to relatively low forward resistance, compared with traditional sailing craft. As a result, such vehicles are often capable of speeds exceeding that of the wind.
The following is a glossary of terminology used in motorsport, along with explanations of their meanings.
The Red Bull Soapbox Race is a soapbox race organised at least once a year by Red Bull. During its final phase, amateur pilots challenge one another by presenting hand-made, motor-less vehicles, judged for their aesthetic, their speed and their road-holding.
The Kinsmen Coaster Classic, also named the All Canada or All-Canadian Coaster Classic, was a youth-oriented soap box race car program that took place in the City of Montreal, Canada from 1938 until the early 1970s. Organized by the Kinsmen Club of Montreal, it was the first city-wide soap box race to be held in the municipality. Cars competing in the event raced downhill, propelled by gravity alone. Competing in two separate classes, boys raced hand-made cars on various streets throughout the city until a permanent site was chosen in Montreal's east end.
{{cite web}}: CS1 maint: bot: original URL status unknown (link)
